645530 has 8 divisors (see below), whose sum is σ = 1161972. Its totient is φ = 258208.

The previous prime is 645529. The next prime is 645571. The reversal of 645530 is 35546.

It can be written as a sum of positive squares in 2 ways, for example, as 537289 + 108241 = 733^2 + 329^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 645496 and 645505.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32267 + ... + 32286.

2⁶⁴⁵⁵³⁰ is an apocalyptic number.

645530 is a deficient number, since it is larger than the sum of its proper divisors (516442).

645530 is a wasteful number, since it uses less digits than its factorization.

645530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64560.

The product of its (nonzero) digits is 1800, while the sum is 23.

The square root of 645530 is about 803.4488160424. The cubic root of 645530 is about 86.4248849501.

The spelling of 645530 in words is "six hundred forty-five thousand, five hundred thirty".